Apparatus and method of preparing a solution containing cations and anions

ABSTRACT

Ions are important for human life. The current method to choose the ions type and the concentration is the traditional chemical dissolving ways. The invention proposes an apparatus and a method of preparing a solution ( 5 ) containing cations and anions. The apparatus comprises: at least one cation releasing module ( 10 ), each of which is configured to release at least one type of cations; at least one anion releasing module ( 12 ), each of which is configured to release at least one type of anions; and a controller ( 14 ) configured to control at least one said cation releasing module ( 10 ) and at least one said anion releasing module ( 12 ) to release corresponding types of ions. The embodiment of the invention automatically prepares a solution by respectively controlling the cations and the anions.

TECHNICAL FIELD

The disclosure relates to preparations of a solution containing cationsand anions, particularly to preparations of a solution containingselective cations and anions.

BACKGROUND OF THE INVENTION

Ions are electrically charged particles which take various functions invivo, as well as in industrial and household applications.

Currently, solutions containing ions are prepared in a traditionalchemical dissolving way. For example, a solution containing K⁺ and Cl⁻can be prepared by dissolving potassium chloride (KCl) in a solvent suchas water or diluting concentrated KCl solution.

However, in this way, anions and cations are added according to a molarratio which is not controllable. For example, by dissolving KCl intowater, K⁺ and Cl⁻ are added with a molar ratio of 1:1. By dissolvingNa₂SO₄, Na⁺ and SO₄ ²⁻ are added with a molar ratio of 2:1.

Therefore, it turns out important and meaningful to have a new methodand apparatus which enables a better control of ion release into asolution.

SUMMARY OF THE INVENTION

According to the aforementioned traditional method, to prepare asolution containing certain type of cations (e.g., K⁺) and anions (e.g.,Cl⁻), the corresponding electrolyte (e.g., KCl) that can dissociate intothe cations and anions is used. Alternatively, one electrolyte with therequired cations and another electrolyte with the required anions areused together to provide the solution of the required cations andanions, which involves other ions not required. In view that differentcombinations of cations and anions may be required in different cases,users have to manage enormous kinds of electrolytes.

Besides, for an electrolyte such as KCl, as long as a concentration ofcations such as K+ is determined, a concentration of anions such as Cl−is hence determined. In case it's needed to prepare a solution with K+in concentration x and Cl− in concentration y where x is different fromy, additional type of chemicals would need to be added into thesolution, such as K₂SO₄, HCl, etc., which means the concentrations ofcations and anions has to be controlled by precise weight measuring ofeach additive beforehand.

Additionally, in preparing the solution, for obtaining some ions such asH⁺, the user may have to use caustic chemicals, e.g. HCl, H₂SO₄ as rawmaterials or intermediate materials of the preparation, which isdangerous for the user.

To better address one or more of aforementioned problems, it would beadvantageous to have an apparatus that automatically prepares a solutionwith cations and anions. It would be also advantageous to separatelycontrol the types of the cations and the anions.

Further, it would be advantageous if the apparatus separately andautomatically controls respective concentration of the anions andcations.

Further, it would be advantageous if a user of the apparatus is free ofdisagreeable caustic chemicals.

In an embodiment of the invention, an apparatus for preparing a solutioncontaining cations and anions comprises:

-   -   at least one cation releasing module, each of which is        configured to release at least one type of cations;    -   at least one anion releasing module, each of which is configured        to release at least one type of anions;    -   a controller configured to control at least one said cation        releasing module and at least one said anion releasing module to        release corresponding types of ions.

The cation releasing module and the anion releasing module canrespectively release certain types of cations and anions into thesolution. Thus, the types of cations and anions in the solution can becontrolled separately.

Further, it would be advantageous to select by the apparatus, frommultiple types of cations and/or anions, required types of cations andanions for the solution. To better address this, in a preferredembodiment, the apparatus comprises at least two cation releasingmodules respectively for different types of cations, and/or at least twoanion releasing modules respectively for different types of anions. Inthis preferred embodiment, with just a few cation releasing modules andanion releasing modules, it can provide solutions with variouscombinations of cations and anions, taking account of both flexibilityand simplicity.

In a preferred embodiment, the cation releasing module comprises: ametal and/or alloy electrode connected to the controller and configuredto immerse in the solution; the controller is configured to apply apositive voltage on the metal and/or alloy electrode such that cationsare released into the solution.

This embodiment provides a specific implementation for the cationreleasing module. The metal and/or alloy electrode is small in size,thus multiple types of electrode can be assembled in the apparatus toprovide the diversity for cation selection. Besides, the metal and/oralloy electrode has a high capacity of cation storage and is convenientfor transportation and use, which would be beneficial for domesticapplications. In one embodiment, an active metal anode can be used togenerate metal cations. In an alternative embodiment, an inert metalanode is used, and water electrolysis would be done and H⁺ cations canbe generated. This can avoid an involvement of a caustic acid, e.g. HCl,H₂SO₄, and thus is safe for the user.

In a preferred embodiment, the cation releasing module comprises a firstcontainer for containing a first electrolyte containing a first type ofcations, the first container having a cationic membrane for separatingthe first electrolyte from the solution, and the controller isconfigured to apply a positive voltage in the first electrolyte suchthat the first type of cations are released into the solution throughthe cationic membrane.

This embodiment provides another specific implementation for the cationreleasing module. Active metal cations such as Na⁺, K⁺, Ca²⁺ and Mg²⁺that is hard to be controllably generated by a metal electrode can bestored and controllably released in this embodiment.

In a preferred embodiment, the anion releasing module comprises a secondcontainer for containing a second electrolyte containing a second typeof anions, the second container has a anionic membrane for separatingthe second electrolyte from the solution, and the controller isconfigured to apply a negative voltage in the second electrolyte suchthat the second type of anions are released into the solution throughthe anionic membrane.

Unlike cations, it could be hard to release anions from electrodes, thusthe embodiment provides a specific implementation for the anionreleasing module.

In a preferred embodiment, the cation releasing module comprises cationcomplexed polymers and/or gels which store the first type of cations andare configured to immerse in the solution, the controller is configuredto electrolyze water in the solution and to generating generate H⁺ ionswhich enter the cation complexed polymers and/or gels and exchange thefirst type of cations out of the polymers and/or gels and into thesolution.

Additionally or alternatively, the anion releasing module comprisesanion complexed polymers and/or gels storing the second type of anionsand is configured to immerse in the solution, the controller isconfigured to electrolyze water in the solution and generate OH⁻ ionswhich enter the anion complexed polymers and/or gels and exchange thesecond type of anions out of the polymers and/or gels and into thesolution.

The embodiment provides still other specific implementations for thecation releasing module and the anion releasing module. The polymersand/or gels are easy to be replaced and cost effective.

In a preferred embodiment, the controller provides the cation releasingmodule and the anion releasing module with currents to release ions; thecontroller is configured to determine an amplitude of the currentflowing through each cation releasing module and flowing time, accordingto a first concentration of the corresponding cations; and/or

the controller is configured to determine an amplitude of the currentflowing through each anion releasing module and flowing time accordingto a second concentration of the corresponding anions;

wherein the controller is configured to control the amplitude of thecurrents and flowing time for the cation releasing module and the anionreleasing module to maintain the total electricity of the generatedcations and the total electricity of the generated anions equal.

This embodiment provides a specific implementation for respectivelycontrolling the concentration of each of the cations and anionsautomatically without involving precise weight measuring. Thisembodiment is quite automatic and flexible for the user to prepare thesolution with required concentrations of ions.

In an embodiment, the apparatus comprises a third container forcontaining the solution. In a varied embodiment, the apparatus can beplaced into the solution, and the size of the apparatus can be small.

Solutions for various usages, e.g. mineral water for drinking, water fortofu making, skin care, disinfection and laundry, should containdifferent types of suitable cations and/or anions. Thus it would beadvantageous to provide the solution according to the practical need. Tobetter address this, in a preferred embodiment, the apparatus furthercomprises: a first unit configured to determine a usage of the solution;a second unit configured to determine a first type of cations and/or asecond type of anions according to the determined usage; and saidcontroller selects the cation releasing module and/or the anionreleasing module according to the first type of the cations and/or thesecond type of the anions.

In an embodiment of the invention, it is provided a method of preparingsolution containing cations and anions, comprising the steps of:

-   -   selecting at least one from at least one cation releasing module        to release respective cations into the solution;    -   selecting at least one from at least one anions releasing module        to release respective anions into the solution.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, aspects and advantages of the present invention will becomeobvious by reading the following description of non-limiting embodimentswith the aid of appended drawings.

FIGS. 1-4 illustrate the block diagrams of different apparatusesaccording to different embodiment of the invention;

FIG. 5 illustrates one specific embodiment of a cation releasing module10 of the apparatus 1 as shown in FIGS. 1-4;

FIG. 6 illustrates another specific embodiment of the cation releasingmodule 10′ of the apparatus 1 as shown in FIGS. 1-4;

FIG. 7 illustrates one specific embodiment of the anion releasing module12 of the apparatus 1 as shown in FIGS. 1-4;

FIG. 8 illustrates an embodiment of the apparatus 1 comprising cationreleasing modules 10 and 10′ and anions releasing modules 12 and 12′with the currents flowing direction.

FIG. 9 is a flow chart illustrating a method 9 according to theembodiment of the invention.

Wherein, the same or similar reference sign refers to the same orsimilar component/module.

DETAILED DESCRIPTION OF EMBODIMENTS

The following lists some typical ions and the respective usages:

-   -   1) Ca²⁺: Calcium is a component of bones and teeth. It also        functions as a biological messenger. The concentration of Ca²⁺        in water affects the efficiency of detergents and sometimes        causes insoluble precipitation.    -   2) K⁺ and Na⁺: Potassium and sodium ions' main function in        animals is to maintain osmotic balance, particularly in the        kidneys.    -   3) Mg²⁺: Most importantly, magnesium ions are a component of        chlorophyll. It also relates to water hardness.    -   4) Cl⁻: chloride ions are important in a balance of an inner        environment of human body, and chloride is also a composition of        the gastric acid.    -   5) CO₃ ²⁻: In blood approximately 85% of carbon dioxide is        converted into carbonic acid radical ions, allowing a greater        rate of transportation.    -   6) PO₄ ³⁻: Adenosine triphosphate is a common molecule which        stores energy in an accessible form. Bone is calcium phosphate.    -   7) Fe^(2/3+): Haemoglobin, the main oxygen carrying molecule has        a central iron ion.

The tervalent Ferric ion can coagulate the proteins and be used inhemostatic agents.

According to an aspect of the invention, it is provided an apparatus 1of preparing a solution containing cations and anions, comprising:

-   -   at least one cation releasing module 10, each of which is        configured to release at least one type of cations into the        solution;    -   at least one anion releasing module 12, each of which is        configured to release at least one type of anions;    -   a controller 14 configured to control at least one said cation        releasing module and at least one said anion releasing module to        release corresponding types of ions.

In different embodiments, the number of either cation releasing modules10 or anion releasing modules 12 can be quite varied depending on theneeds. FIGS. 1-4 show the block diagrams of the different apparatuses 1according to different embodiments of the invention. In an embodimentshown in FIG. 1, one cation releasing module 10 and one anion releasingmodule 12 is comprised in the apparatus 1. In this embodiment, the typesof cations and anions in the solution are fixed. In a more complicatedembodiment as shown in FIG. 2, the apparatus 1 comprises one anionreleasing module 12 and several cation releasing modules 10, 10′ and 10″to release a fixed anions together with any or any combination of thecations. Also, similarly, in a more complicated embodiment as shown inFIG. 3, the apparatus 1 comprises one cation releasing module 10 andseveral anion releasing modules 12, 12′ and 12″ to release a fixedcations together with any or any combinations of the anions. Further, inan embodiment as shown in FIG. 4, the apparatus 1 comprises severalcation releasing modules 10, 10′ and several anion releasing modules 12,12′ to release different combinations of anions and cations. It shouldbe appreciated that in other embodiments the number of either or both ofanion releasing module and cation releasing module can be different fromthat illustrated in FIGS. 1-4.

According to an aspect of the invention, as shown in FIG. 9, it isprovided a method of preparing solution containing cations and anions,comprising the steps of:

-   -   S94: selecting at least one from at least one cation releasing        module to release respective cations into the solution;    -   S96: selecting at least one from at least one anions releasing        module to release respective anions into the solution.

Having described the varying structures of the apparatus and the methodaccording to embodiments of the invention, the following part willelucidate different specific embodiments for the cation releasing moduleand the anion releasing module and the control applied thereto.

The Cation Releasing Module

In one embodiment, the cation releasing module 10 comprises a metaland/or alloy electrode 2 connected to the controller and configured toimmerse in the solution. And the controller is configured to apply apositive voltage on the metal and/or alloy electrode such that cationsare released into the solution.

As shown in FIG. 5, the electrode 2 is made from active metal A and usedas the anode. The electrode 2 immerses in the solution 5, and when apositive voltage is applied on the electrode 2 (with a negative voltageis applied in the solution 5), the metal atom in the electrode 2 loseselectrons, and the cations A^(m+) are released from the electrode 2 andinto the solution 5. Preferably in some embodiments, active metalcations like Al³⁺, Zn²⁺, Fe³⁺, Sn²⁺, Cu²⁺ and Ag⁺ can be released inthis strategy. The electrode equations are listed as follows:

Al-3e ⁻→Al³⁺;

Zn-2e ⁻→Zn²⁺;

Fe-3e ⁻→Fe³⁺;

Sn-2e ⁻→Sn²⁺;

Cu-2e ⁻→Cu²⁺; and

Ag-e ⁻→Ag⁺

Wherein, e⁻ stands for an electron.

In an alternative embodiment, an inert metal electrode such as Ptelectrode is used as the anode, and water electrolysis would be done atthe anode and ft cations can be generated in the solution. This cangenerate ft cations without dissolving a caustic acid addictive, e.g.HCl, H₂SO₄, and hence it is safe for the user.

The metal and/or alloy electrode is small in size, thus multiple typesof electrode can be installed in the apparatus 1 to provide diversityfor the cation selection.

As to the method aspect, the first selecting step comprises: applying apositive voltage on the metal and/or alloy electrode 2 such that thecations are released into the solution.

In another embodiment, as shown in FIG. 6, the cation releasing module10′ comprises a first container 3 for containing a first electrolyte 6containing a first type of cations A^(m+), and the first container 3 isfor example configured to immerse into the solution 5. The firstcontainer 3 has a cationic membrane 30 for separating the firstelectrolyte 6 from the solution 5, and the cationic membrane 30 onlyallows cations pass through, namely from the first container 3 to thesolution 5. And the cation releasing module 10′ comprises an anode 32with one end immersing in the first electrolyte 6 and the other endconnected to the controller 14 (not shown in FIG. 6) which is configuredto apply a positive voltage to the first electrolyte 6 via the anode 32.Cations H⁺ are generated in the first electrolyte 6. To maintain theelectric neutrality in the first electrolyte 6, the cations A^(m+) flowout of the first electrolyte 6 through the cationic membrane 30 into thesolution 5.

This embodiment provides another specific implementation for the cationreleasing module. Active metal cations such as Na⁺, K⁺, Ca²⁺ and Mg²⁺that is hard to be controllably generated by a metal anode can be storedand controllably released in this embodiment.

As to the method aspect, the first selecting step S94 comprises applyinga positive voltage to the first electrolyte such that the cations arereleased into the solution through the cationic membrane 30.

In still another embodiment, other materials that can release cationsunder electrical control could also be used as the cation releasingmodule, such as polymer, gel. Specifically, the cation complexed polymeror gel storing this type of cations is configured to immerse in thesolution, and the controller 14 is configured to electrolyze water inthe solution to generate H⁺ cations. The H⁺ cations enter into thecation complexed polymer and/or gel and exchange this type of storedcations out of the polymer or gel under the effect of the electricfield, and this type of cations enters into the solution under theeffect of the electric field. In one implementation, one cationreleasing module can contain one kind of polymer which stores andrelease one type of cations. In case that several types of cations areneeded, several cation releasing modules respectively with correspondingpolymer should be deployed. In a varied implementation, one cationreleasing module can contain one polymer stores several types ofcations, or contain several polymers respectively stores one type ofcations. In this varied implementation, the several types of cationswould be released simultaneously.

The above description gives implementations for the cation releasingmodule 10, and the following description will elucidate implementationsfor the anion releasing module 12.

The Anion Releasing Module

In one embodiment, as shown in FIG. 7, the anion releasing module 12comprises a second container 4 for containing a second electrolyte 7containing a second type of anions B^(n−), and the second container 4 isfor example configured to immerse into the solution 5. The secondcontainer 4 has an anionic membrane 40 for separating the secondelectrolyte 7 with the solution 5, and the anionic membrane 40 onlyallows anions pass through, namely from the second container 4 to thesolution 5. And the cation releasing module 10 comprises a cathode 42with one end immersing in the second electrolyte 7 and the other endconnected to the controller 14 which is configured to apply a negativevoltage to the second electrolyte 7 via the cathode 42. Anions OH⁻ aregenerated in the second electrolyte 7. To maintain the electricneutrality in the second electrolyte 7, anions B^(n−) flow out of thesecond electrolyte 7 through the anionic membrane 40 into the solution5.

In an example, acid radicals such as Cl⁻, SO₄ ²⁻ are required in thesolution 5. In the prior arts, the user may have to manipulate HCl orH₂SO₄, and this is dangerous. When using the embodiment of theinvention, the anion releasing module 12 can use a solution of KCl orNa₂SO₄ as the second electrolyte 7. The acid radicals are releasedwithout the manipulation of the user, and the user is free of thecaustic chemicals.

As to the method aspect, the second selecting step comprises: applying anegative voltage to the second electrolyte such that the anions arereleased into the solution through the anionic membrane 40.

In still another embodiment, other materials that can release anionsunder electrical control could also be used as the anion releasingmodule, such as polymer, gel. Specifically, anion complexed polymer orgel storing this type of anions is configured to immerse in thesolution, and the controller is configured to electrolyze water in thesolution and generate OH⁻ anions. The OH⁻ anions enter into the anionpolymer or gel and exchange this type of stored anions out of thepolymers or gels under the effect of the electric field, and this typeof anions enters into the solution under the effect of the electricfield. In one implementation, one anion releasing module can contain onekind of polymer which stores and release one type of anions. In casethat several types of anions are needed, several anion releasing modulesrespectively with corresponding polymer should be deployed. In a variedimplementation, one anion releasing module can contain one polymerstores several types of anions, or contain several polymers respectivelystores one type of anions. In this varied implementation, the severaltypes of anions would be released simultaneously.

Generally, unlike metal anodes that release metal cations, most cathodeitself can't release anions, therefore the above embodiments with ananion-contained solution and an anion-complexed polymer and/or gel makeit possible to release anions.

The above description elucidates the structure of the apparatus 1 andspecific implementations of the cation releasing modules 10 and anionreleasing modules 12. The following description will elucidate how tocontrol each of the modules to obtain required concentrations of each ofthe cations and anions.

An apparatus 1 with two cation releasing modules 10 and two anionreleasing modules 12 is taken as an example and illustrated in FIG. 8.The controller 14 provides the cation releasing modules 10 and the anionreleasing modules 12 with currents to release ions, and the controller14 controls the amplitude of current and current flowing time for eachmodule to obtain required concentration. To make it easy to understand,all of the cation releasing modules 10 and 10′ are similar as that inFIG. 6 and the anion releasing modules 12 and 12′ are similar as that inFIG. 7. The apparatus further comprises a third container 50 forcontaining the solution 5, and those modules are placed within thecontainer 50 and configured to immerse into the solution 5.

The concentrations of released cations and anions are closely relatedwith the electricity (Q=t×I) provided for each module by the currentover the time. The equations could be written as:

m×C _(A1) ^(m+) ×V=t×I _(A1) ; n×C _(A2) ^(n+) ×V=t×I _(A2);

o×C _(B1) ^(o−) ×V=t×I _(B1) ; p×C _(B2) ^(p−) ×V=t×I _(A2).

wherein m, n, o and p are the charge numbers of the cations and anions;C_(A1) ^(m+), C_(A2) ^(n+), C_(B1) ^(o−) and C_(B2) ^(p−) are theconcentrations of the cations and anions; V is the volume of thesolution S, I_(A1), I_(A2), I_(B1) and I_(A2) are the currents flowthrough the modules; t is the time for which the current flows andreleases the ions. Given a required concentration of the cations andanions, the controller 14 determines the amplitude of the currentflowing through the corresponding module and flowing time, according tothe concentration of the corresponding ions together with charge numbersof the ions and a volume of the solution S. For example, for A1^(m+),given the required concentration C_(A1) ^(m+), the current I_(A1) andtime t shall meet the following expression:

t×I _(A1) =m×C _(A1) ^(m+) ×V.

To maintain the electric neutrality, cations and anions released shouldsatisfy the following equation:

m×C _(A1) ^(m+) +n×C _(A2) ^(n+) =o×C _(B1) ^(o−) +p×C _(B2) ^(p−)

Moreover, the total amount of ions released could be monitored andcontrolled by the total electricity flow through the ion modules, whichcan be recorded as:

Q _(total) =Σt×I _(Ai) =Σt×I _(Bi) =Σm _(i) ×C _(Ai) ^(mi+) ×V=Σo _(j)×C _(Bj) ^(oj−) ×V.

For example,

1. When I_(A1)=I_(B1)≠0 and I_(A2)=I_(B2)=0, then A1^(m+) and B1^(o−)are released with a concentration ratio of o:m.

2. When I_(A1)=I_(B2)≠0 and I_(A2)=I_(B1)=0, then A1^(m+) and B2^(q−)are released with a concentration ratio of q:m.

3. When I_(A1)=2I_(B1)=2I_(B2) and I_(A2)=0, then A1^(m+), B1^(o−) andB2^(q−) are released with a concentration ratio of 2oq:mq:mo.

4. By controlling the current distribution, complex combination ofdifferent cations and anions can be released.

This embodiment provides a specific implementation for respectivelycontrolling the concentration of each of the cations and ions. Thisembodiment is quite automatic and flexible for the user to prepare thesolution with required concentrations of ions.

As to the method aspect, the method further comprises:

determining the amplitude of the current flowing through each cationreleasing module 10 and flowing time, according to a first concentrationof the corresponding cations; and/or

determining the amplitude of the current flowing through each anionreleasing module 12 and flowing time according to a second concentrationof the corresponding anions;

and comprises:

controlling the amplitude of the currents and flowing time for thecation releasing module 10 and the anion releasing module 12, tomaintain the total electricity of the generated cations and the totalelectricity of the generated anions equal.

In the implementation, the solution for various usages, e.g. mineralwater for drinking, tofu making, skin care, disinfection or laundry,should contain different types of suitable cations and/or anions. Thusit would be advantageous for one single apparatus to provide diversesolutions according to different practical needs. To better addressthis, in a preferred embodiment, the apparatus further comprises:

a first unit configured to obtain information concerning a usage of thesolution;

a second unit configured to determine a first type of the cations and/ora second type of the anions in the solution according to the obtainedinformation;

and the controller 14 selects at least one said cation releasing module10 and/or at least one said anion releasing module 12 according to thedetermined first type of the cation and/or the determined second type ofthe anions.

For example, to prepare mineral water for drink, the cations are Na⁺,K⁺, Ca²⁺ and Mg²⁺, meanwhile the anions are SO₄ ²⁻ and Cl⁻. To preparewater for skin care and oral care, the cations can be Ca²⁺, Mg²⁺, Zn²⁺and the anions are NO₃ ⁻ or SO₄ ²⁻. To prepare water for disinfectionand hygiene, the cations can be Ag+, H+, and the anions can be S₂O₈ ²⁻.In a further implementation, the solution is not used directly butundergoes a further processing, for example the usage of the solution isbeing electrolyzed to generate corresponding gases, such as Cl₂. In thiscase, the controller 14 selects modules to release corresponding ionsinto the solution, for example selects a Cl⁻ releasing module to releaseCl⁻ into the solution so as to generate Cl₂.

The first unit configured to obtain the information can be a userinterface configured to receive the input from the user. In case thatthe apparatus is attached to and output the solution to a device, suchas water dispenser, tofu making machine, washing machine, adapted toutilize this solution, the interface can be a machine to machineinterface to receive the instruction from the device. In anotherembodiment, the first unit can also be a memory prestoring theinformation concerning the usage of the solution.

As to the method aspect, as shown in FIG. 9, before steps S94 and S96,the method further comprises the steps of:

-   -   S90: obtaining information concerning a usage of the solution;        and    -   S96: determining a first type of the cations and/or a second        type of the anions in the solution according to the obtained        information;

said two selecting step respectively selects the cation releasing module10 and/or the anion releasing module 12 according to the determinedfirst type of the cations and/or the determined second type of theanions.

Those ordinary skilled in the art could understand and realizemodifications to the disclosed embodiments, through studying thedescription, drawings and appended claims. For example, each of thecation releasing modules can contain and release two or more types ofthe cations simultaneously, such as Na⁺, Ca²⁺ and Mg²⁺, and each of theanion releasing modules can contain and release two or more types of theanions simultaneously. All such modifications which do not depart fromthe spirit of the invention are intended to be included within the scopeof the appended claims.

The word “comprising” does not exclude the presence of elements or stepsnot listed in a claim or in the description. The word “a” or “an”preceding an element does not exclude the presence of a plurality ofsuch elements. In the practice of present invention, several technicalfeatures in the claim can be embodied by one component. In the claims,any reference signs placed between parentheses shall not be construed aslimiting the claim. “At least one of A, B and C” should cover any one ofthe following: A; B; C; A and B; A and C; B and C; A and B and C.

1. An apparatus of preparing a solution containing cations and anions,comprising: at least one cation releasing module, each of which isconfigured to release at least one type of cations; at least one anionreleasing module, each of which is configured to release at least onetype of anions; a controller configured to control at least one saidcation releasing module and at least one said anion releasing module torelease corresponding types of ions; wherein, the apparatus comprises atleast two cation releasing modules (10, 10′) and/or the apparatuscomprises at least two anion releasing modules (12, 12″).
 2. (canceled)3. An apparatus according to claim 1, wherein, the cation releasingmodule comprises: a metal and/or alloy electrode connected to thecontroller and configured to immerse in the solution; the controller isconfigured to apply a positive voltage on the metal and/or alloyelectrode such that cations are released into the solution.
 4. Anapparatus according to claim 1, wherein the cation releasing modulecomprises a first container for containing a first electrolytecontaining said type of cations, the first container having a cationicmembrane separating the first electrolyte with the solution, thecontroller is configured to apply a positive voltage to the firstelectrolyte such that said type of cations are released into thesolution through the cationic membrane.
 5. An apparatus according toclaim 1, wherein the anion releasing module comprises a second containerfor containing a second electrolyte containing said type of anions, thesecond container has an anionic membrane for separating the secondelectrolyte with the solution, the controller is configured to apply anegative voltage to the second electrolyte such that said type of anionsare released into the solution through the anionic membrane.
 6. Anapparatus according to claim 1, wherein the cation releasing modulecomprises a cation complexed polymer and/or gel storing the cations andconfigured to immerse in the solution, the controller is configured toelectrolyze water in the solution and generate H⁺ ions which enter thecation complexed polymer and/or gel and exchange said type of cationsout of the polymer and/or gel and into the solution; and/or the anionreleasing module comprises an anion complexed polymer and/or gel storingthe anions and configured to immerse in the solution, the controller isconfigured to electrolyze water in the solution and generate OH⁻ ionswhich enter the anion complexed polymers and/or gels and exchange saidtype of anions out of the polymers and/or gels and into the solution. 7.An apparatus according to claim 1, wherein, the controller provides thecation releasing module and the anion releasing module with currents torelease ions; the controller is configured to determine an amplitude ofthe current flowing through each cation releasing module and flowingtime, according to a first concentration of the corresponding cations;and/or the controller is configured to determine an amplitude of thecurrent flowing through each anion releasing module and flowing timeaccording to a second concentration of the corresponding anions; whereinthe controller is configured to control an amplitude of the currents andflowing time for the cation releasing module and the anion releasingmodule to maintain the total electricity of the generated cations andthe total electricity of the generated anions equal; and the apparatusfurther comprises: a third container for containing the solution.
 8. Anapparatus according to claim 1, further comprising: a first unitconfigured to obtain information concerning a usage of the solution; asecond unit configured to determine the a first type of the cationsand/or the a second type of the anions in the solution according to theobtained information; said controller selects at least one said cationreleasing module and/or at least one said anion releasing moduleaccording to the determined first type of the cations and/or thedetermined second type of the anions.
 9. A method of preparing solutioncontaining cations and anions, comprising the steps of: selecting atleast one from at least one cation releasing module to releaserespective cations; selecting at least one from at least one anionsreleasing module to release respective anions; wherein the cationreleasing module comprises at least two modules respectively fordifferent types of cations, and/or the anions releasing module comprisesat least modules respectively for different types of cations. 10.(canceled)
 11. A method according to claim 9, wherein the cationreleasing module comprises: a metal and/or alloy electrode connected toan anode and configured to immerse in the solution; and the firstselecting step comprises: applying a positive voltage on the metaland/or alloy electrode such that the metal cations are released into thesolution.
 12. A method according to claim 9, wherein the cationreleasing module comprises a first container for containing a firstelectrolyte containing the type of cations, the first container having alayer of cationic membrane for separating the first electrolyte with thesolution, and the first selecting step comprises: applying a positivevoltage to the first electrolyte such that the cations are released intothe solution through the cationic membrane.
 13. A method according toclaim 9, wherein the anion releasing module comprises a second containerfor containing a second electrolyte containing the anions, the secondcontainer has a layer of anionic membrane for separating the secondelectrolyte with the solution, and the second selecting step comprises:applying a negative voltage to the second electrolyte such that theanions are released into the solution through the anionic membrane. 14.A method according to claim 9, wherein, the first and second selectingstep provides the cation anion releasing module and the anion releasingmodule with current to release ions; the method further comprises:determining the amplitude of the current flowing through each cationreleasing module and flowing time, according to a first concentration ofthe corresponding cations; and/or determining the amplitude of thecurrent flowing through each anion releasing module and flowing timeaccording to a second concentration of the corresponding anions; andcomprises: controlling the amplitude of the currents and flowing timefor the cation releasing module and the anion releasing module, tomaintain the total electricity of the generated cations and the totalelectricity of the generated anions equal.
 15. A method according toclaim 9, further comprising the steps of: obtaining informationconcerning a usage of the solution; determining a first type of thecations and/or a second type of the anions in the solution according tothe obtained information; said two selecting step respectively selectsthe cation releasing module and/or the anion releasing module accordingto the determined first type of the cation and/or the determined type ofthe anions.